Os ventiladores refrigeram não apenas os freios, mas também os sensores de temperatura, em taxas diferentes. A diferença de temperatura é uma medida para corrigir essa anomalia. Do documento Operação adequada dos freios de carbono pelo suporte de operações de voo da Airbus:
... the temperature indicated in the cockpit when the brake fans are running is significantly lower than the temperature indicated when the brake fans are OFF. This is because the brake fans are ventilating the brake temperature sensor that is not located inside the material itself. Therefore, as soon as the brake fans are running, the indicated brake temperature decreases almost instantaneously.
... For all brake types, when the fans are running, the difference ranges typically from approximately 50°C at 100°C actual brake temperature up to about 150°C at 300°C actual brake temperature.
... When fans are selected, the warning will disappear instantaneously, but the takeoff must be delayed until the indicated temperature consistently decreases below 150°C (for a warning set at 300°C)